Electromagnetic relay



May 18, 1937. H. c. PYE' 2,081,019

ELECTROMAGNETIC RELAY Filed March 25, 1932 Inuntor Harold C. FE:

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Patented May 18, 1937 UNITED STATES ELECTROMAGNETIC Harold 0.1m, ou'ruk, 111., assignor, bymesne assignments, to Associated Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Application March 25, 1932, Serial No. 601,114

18 Claims.

This invention relates in general to electromagnetic relays, but more particularly to electropolarized relays having a, number of windings, and the principal object of the invention. is to provide a new andimproved electro-polarized relay which may be operated over wider limits of voltages and in a larger number of different circuit arrangements. Y V

A relay of this general type is disclosed in Patent No. 1,673,884, granted June 19, 1928 to H. C. Rye and this patent describes a number of usages for a relay of this type. This relay, due to its construction, is arranged so that upon the energization of the polarizing winding a magnetic flux is created over a shunt path which holds the armature against a back-stop, preventing its energization. When current, however, is connected to the other winding in such a direction so as to assist the flux in,the polarizing winding, the ar- If the circuit through the polarizing winding should now be interrupted the operating winding alone will hold up thearmature and likewise if the circuit to the operating winding is opened the polarized winding will hold it up. If the current through the operating winding should be reversed it will create a flow of magnetism around the shunt path opposing that created by the polarized winding and assist the armature to restore.

The above structure, it will be observed, requires separate energizing circuits for the polarizing and the operating windings, and the relay, therefore, has its armature responsive only to two separate and distinct circuit changes. This arrangement works satisfactory under the conditions and usages described in the above patent. In the art of automatic telephony, however, where relays of this type are useful, certain types of relays are required which are energized and deenergized in rapid succession, such as the line'relay of the selecting switches which are responsive to the dial impulses from a subscriber at a substation. 'Or- 'dinary single or double wound relays as commonly used operate fairly satisfactory in response to the impulses, provided the line conditions are ideal. In most cases, however, there is always a certain amount of leakage. across the line conductors which may or may not be of diflerent resistance and the ordinary line relay will respond quickly to these conditions within only very limited ranges of operation. Accordingly, it is an object of this invention to provide a relay as constructed in the above patent in an improved circuit arrangement suitable for. use as a line relay of the selecting switches. A relay according to the invention will operate within wider limits of line leakage or extreme variations in line conditions.

A further object of the invention is to design an electro-magnetic relay in which only a rapid change or surge of current will be effective to operate the armature of the .relay so that it can be used as a line relay in a line having considerable leakage on it.

A further'object resides in providing a relay constructed according to the above patent and which is provided with a number of windings all energized, from the same external source, and at the same time, in order to control the armature.

A particular feature of the invention resides in providing a relay of the aforesaid type in which the movement of the armature is accelerated in both its operating and restoring 'actions.

The invention will be described in accordance with the accompanying sheet of drawings which shows a number of diflerent modifications in diagrammatic form.v Fig.- 31 of the drawing illustrates a constructionof relay according to the aforesaid patent in which an additional inductive winding is provided to assist the armature in its operating and releasing functions; Fig. 2 is a modification of Fig. i'showing -a transformer connected between the two windings of the relay; Fig. 3 shows a relay having a normally discharged condenser connected in series with the operating winding and parallel with the polarizing winding in such a manner so as to assist in the operation and restoration of the armature; Fig. 4 is a modiflcationoi Fig; 3 inwhich the condenser is normally in a charged state and the discharge and charging ofit controls the operation of the armature; Figs. 5 and 6' are side and front views of the physical structure of a relay similar to that disclosed in the patent and which is a modiflcation oi the type shown in Fig. 1.

Referring now more particularly to Fig. 1 the relay structure 'comprises, as shown diagrammatically, a soft iron core I, a heel piece 2 screwed onto the end of the core I and having an armature l pivoted on the other end. The armature I is arranged to operate suitable contact springs which are not shown. Themagnetic member 5 encircles the core between its ends and separates the windings A and B from winding C. Magnetic member 5 forms part of a magnetic shunt having a leg 4 which has one end serving as a backstop for the armature 3. The winding A is the polarizing winding of the relay and for convenience, in order to illustrate the operation, a source of current is indicated in its circuit together with a key K for closing the circuit for the winding. The windings B and C are connected together in series and arranged on the core so that they oppose each other. No battery or source of current is included in their circuits.

The key K of Fig. 1 upon being operated closes a battery source through the polarizing winding A on the core I in the direction indicated by the arrows. This current flow in the winding A induces a flow of current in the winding B. As the winding C is connected in series with winding B this flow of current likewise energizes this winding. The current flowing through winding A will continue to do so as long as the key K is closed. However, thecurrent induced in winding B does not continue to flow after the initial surge due to the building upoi' the current in A. B is therefore in eflect the secondary of a transformer of which A is the primary, and only when sudden changes of current flow occur in the winding A will any current flow in the winding B. As long as the winding A remains in a stablecondition no further current flow takes place in B and C. The winding A is wound in such a direction upon the core that the current flowing through it creates a flow of magnetic flux in the direction indicated by the arrow. This renders the right-hand end of the core I a south pole which extends to the heel piece 2 and the end of the armature 3. The armature 3 is, therefore, also rendered a south pole. The winding B tends to produce a flow of magnetic flux through the core I which is in opposition to that generated by the winding A. The winding C, however, is wound in the opposite direction from B, and is connected up so that current flow through it is in the same direction as that through winding A. It accordingly produces a flow of magnetic flux in the same direction as that produced by the winding A. The flow of current through winding C produces a flux tending to render the left-hand end of the core I a north pole. The magnetic shunt member 4 has a certain amount of flux flowing through it, but this fluctuates widely as the current builds up in windings A and B and then out of winding B again, but the tendency is to render this member less north polarity the instant winding C is energized. As the-armature 3 is tending to be south polarity and the magnetic member 4 less north, while the left-hand end of the core is of strong north polarity, an attraction exists between the lefthand end of the core I and the armature 3. whereupon the armature is immediately attracted. After the initial surge of current through winding B has died down the winding A will remain energized as long as key K is operated, and this winding alone will hold the armature 3 attracted to the left-hand end of the core I over a magnetic circuit including the core I, armature 3, and the heel piece I. The magnetic shunt 4,

although slightly of north polarity, will not be eflective, due to the large air gap between it and the armature. a

When the key K is restored, interrupting the flow of current through the winding A from the battery, the magnetic flux generated by the winding A-and extending over a path from the core I, armature 3, and back over the heel piece 2, decays. The opening of the circuit through the winding A causes the flux to decay and thereby induces a flow of current in the winding 8..

in such a direction that the current flowing through winding C will be reversed from what it was when the flux was building up. The winding limitations.

C therefore produces a flow of magnetic flux in a direction opposite to that which the winding A originally produced. The polarity of the heel piece 2, as well as the armature 3 remains south polarity, the same as it was. Due to the reverse current flow in the winding C, however, the lefthand end of the core I produces a south pole and the armature 3 being or the same polarity, it is repelled and as the magnetic member 4 has assumed a north polarity at this time a powerful attraction exists between the armature 3 and the back-stop of the magnetic member 4. The magnetic circuit arrangement of Fig. 1 is therefore such that the armature 3 is powerfully and rapidly attracted, while its restoring action is considerably accelerated.

As is well known, the lines in a telephone system have a certain amount of leakage existing between the two line conductors which produces high resistance shunt paths across them, rendering the line relays oi the automatic switches, used in establishing connections, operative Satisiactorily only within relatively narrow current For illustrative purposes, the resistance R of Fig. 1 has been indicated in dotted lines to represent the high resistance shunt on a line while the key K simulates the subscriber's calling device or impulse sender. With the shunt condition existing in the line, more or less current will be continuously flowing through the polarizing winding A, tending to keep this winding in a stable energized condition, because the shunt is not of such a character as to produce sudden changes-or surges in the current flow. As long as this condition exists no current is induced into the winding B, and this in turn cannot energize operating winding C. The winding A being stably energized, it produces a constant flow .of flux in the magnetic circuit including core i magnetic member 5, magnetic shunt member 4, armature 3, heel piece 2 and back to the core I;

holding the armature in its normal position.

However, as soon as key K is closed, a change in the current flow through winding A takes place because the key closes a shunt path around the high resistance R across the line conductors. An inductive kick is thereby induced into the winding B and this in turn flows into the operating winding C. Winding C produces a flux through the core I in a direction to assist that flowing therein consequent to the energization of winding A. The armature 3 is repelled by the shunt member 4 and attracted to the core 8 until the armature comes into the influence of the core and is then strongly attracted by the magnetic flux established in the core by the windings A and B.

In the modification shown in Fig. 2, the transformer T having a primary winding P and a secondary winding 8 is connected in circuit oi the relay to take the place of the winding B of Fig. 1.- The action of this relay is the same in that upon the closure of the key K winding A is energized in series with the primary winding P or the transformer T. The surge oi current through the winding P when it is energized induces a current flow to the winding S. The current flowing through the winding A induces a flow ot flux in the core in such a direction as to render the right-hand end 0! the core I south polarity and as this extends to the heel piece 3 the armature 3 is, therefore, likewise rendered south polarity. A portion or this flux extends to the magnetic member 5 and through the shunt path member 4 to the end opposite the armature rendering it slightly north polarity. The primary winding of the transformer T induces a.

flow of current through the secondary winding 8 in such a direction through the transformer 5 T that the winding C is energized so as to assist dwhile the right-hand end of the core opposite the magnetic member 5 is rendered south polarity tending to oppose the flux in the shunt path I qgflnd render it neutral. or of south polarity. The

I rmature I being of south polarity, the member 5 ,4 being of south polarity or neutral, and the lefthand end of the core I of north polarity, a powerful attraction exists between these two and the armature 3 is immediately attracted. It remains in its attracted condition as long as the winding A has current flowing through it or remains in a stable condition, the initial surge of current through the transformer T and induced in the secondary S having in the meantime been dissipated. When the key K is opened the current in winding A ceases to flow resulting in the decaying of the flux flowing through the magnetic circuit comprising the core I, armature 3, heel piece 2, and back over the core again. As a result, of the opening of the circuit of winding A a flow of current is induced in the secondary of the transformer T and this in turn through the winding C, causing a reversal of the flow of flux in the left-hand end of the core tending to oppose that originally flowing in the magnetic cir- 5 cuit. This reversal assists in restoring the armature I by rendering the left-hand end of the core south polarity and as the armature 3 is already of this polarity, it is rapidly repelled, and as the back-stop of the magnetic member 4 is of north position. a Referring now to Fig. 3, this modiflcation'shows the idea of utilizing the action of a condenser to operate the armature of a relay instead of 5 providing an additional winding energized by the inductive effect of the polarizing winding. The condenser D is placed in series with the operating winding C of the relay and in parallel with the winding A which is the polarizing winding. In this arrangement the condenser D is normally in a'state of discharge. When the key K is closeda source of battery is connected across the polarizingwinding A of the relay and this results in a flux flowing in the core I in the direction indicated by the arrow. The flow of current through the winding A from the battery also extends in parallel to the winding C and condenser D and charges up the condenser D to its full potential; The winding C energizes in such a direction as 60 to set up a flow of flux in the core to assist that generated by the winding A. The combined energization of the windings A and C results in the tendency to form a north pole on the left-hand end of the core I and south pole on the righthand end of the core. Magnetic shunt leg 4 which is rendered north polarity by winding A is opposed by the flux from winding C resulting in the end of this member being only slightly north polarity. The armature I, being fixed to the heel piece 2, is rendered south polarity. A strong attraction, therefore, exists between the lefthand end of the core I and thearmature I resulting in the attraction of the same and the operation of the armature. When the key K is 5 opened, and the battery disconnected from the polarity at this time, it is retracted to normal winding A, the inductive eflect of this windins causes the condenser D immediately to discharge in a reverse direction through the winding ,0. This results in the reversal of the flux flowing through that portion of the core'containing winding C. The left-hand end of the core I- is now rendered south polarity and as the armature 3 is already of that polarity a repelling action takes place. The left-hand end of the magnetic member 4 being of north polarity, a strong attraction exists between it and the armature, and results in the rapid restoration of the same to normal.

From the foregoing description it is seen that the closure of the circuit and the energization of winding C, together with the charging of the condenser D, immediately attracts the armature and when the circuit is opened, winding A causes the condenser to discharge through the winding C in the reverse direction to strongly restore the armature to its normal position. If it should occur that there is a high resistance leak existing across the two conductors, the winding C would not be energized and the condenser D would not be charged, due to the stable condition of the winding A, but only in case, a sudden surge of current takes place, short-circuitlng the leakage nection in the series circuit of windings A and B and the battery. if the key K is now closed, the windings A and B are connected in, series across the battery resulting in the discharge of the condenser D through the winding C. Windings A and B set up a flux path as indicated by the direction of the arrows, while winding C, which has been energized through the discharge of the condenser D in the same direction as A sets up a flux in a similar direction, resulting in a magnetic circuit extending over the core I, armature 3, heel piece 2, and back over the core I to attract the armature. The magnetic member 4 is slightly of a north polarity but has a tendency to south polarity due to winding C. When the key K is opened the condenser D is immediately charged up but in the reverse direction. During the charging action of the condenser D the current flow in the winding C of flux in a reverse direction so as to rapidly repel and restore the armature l to normal position. The condenser. after this remains in its charged state. As in Fig. 3, this arrangement will operate over extreme variations in line conditions.

Fig. 5 shows a side view and Fig. 6 a front view, with the armature and heel. piece removed, of a modified relay constructed in accordance with the diagrammatic showing of Fig. 1. In Fig. 1, it will be noted, the windings B and C are each shown in the form of a number of turns of a conductor about the core I of the relay. It will be appreciated that each of these windings may be of any number of turns desired, depending upon the voltage used and the degree of attraction of the armature 3. In the form shown in Figs. 5 and 6, the windings B and C both take the form of a single turn. This is brought about by providing a copper slug'having a hole extendingthrough its center so thatit can be easthereby separating the slug into two sections representing the windings B and C. In order to make the slug effective as two connected windings, a longitudinal slot 1 is cut in the slug reentrant to the core i. As shown more clearly in Fig. 6, the slug as arranged is in eiiect two single turns B and C connected together and separated by the magnetic member 5 from which projects the shunt member 4. As arranged the windings B and C are connected in opposition and are energized by the winding A which may be of the conventional type of any number of turns of wire. The operation of the device is exactly the same as that described in connection with Fig. 1. The copper slug, due to the slot 1 eliminates the possibility ot-the generation of eddy currents and does not render the device slow-acting in its characteristics.

From the foregoing description of each of the modifications illustrated and described, it will be seen that the flow of flux over the magnetic circuit pointed out is similar in each instance and in all cases the armature is immediately attracted without any lag and when desired, it is forcibly and quickly restored to its normal po- 'sition.

What isclaimed is:

1. In an electromagnetic device, a magnetic core, an armature, a polarizing winding and an operating winding on the core, means responsive to the energization of said polarizing winding for simultaneously energizing said operating winding to control said armature, and a magnetic shunt member on said core between said windings.

2. In an electromagnetic device, a magnetic core, an armature, a polarizing winding and an operating winding on said core, means responsive to the energization 01' said polarizing winding for inducing a flow of current in said operating winding to operate said armature, and a magnetic shunt member on said core influenced by one of said windings for controlling said armature.

-3. In an electromagnetic device, a magnetic core, an armature, a polarizing winding and an operating winding on said core, means for energizing said polarizing winding, means responsive to the energization of said polarizing winding for energizing said operating winding to operate the armature, and a magnetic shunt mem bet on said core influenced by said operating winding for controlling said armature.

4. In an electromagnetic device, a magnetic core, an armature, a polarizing winding on one end of said core, an operating winding on the other end oi said core for controlling said armature, an inductive windingconnected to said operating winding and on said core between the operating and the polarizing windings, and means responsive to the energization of said polarizing winding-for inducing a flow of current in said inductive winding to energize the operating winding and attract the armature to the core.

5. In anelectromagnetic relay, a magnetic core, a heel piece attached to one end of said core, an armature pivoted to said heel piece opposite the other end 01 the core, a polarizing winding normally energized and supported on the'heel end oi the core, an operating winding on the armature end of said core, an inductive winding on the core between said operating and said polarizing windings, means for maintaining the armature in its normal position as long as said polarlzed winding is in a stable energized condition,

means responsive to changes of current value in said polarizing winding for inducing a flow of current in the inductive winding, said inductive winding being connected to said operating winding to energize it, and means responsive to the energization of said operating winding for moving said armature to its operating position.

6. In an electromagnetic device, a magnetic core, an armature adjacent one end of the core, a'polarizing winding and an operating winding on said core, a magnetic member projecting from the core between said windings and extending oppmite the end oi the armature end of the core, a normally discharged condenser connected in said operating winding, means for energizing said polarizing winding and charging said condenser, means responsive to the stable e-iergization 01' said polarizing winding for creating a flow of magnetic flux through said magnetic member, the armature, and the core, to prevent the operation of the armature, and means responsive to the charging of said condenser for energizing said operating winding to create a magnetic flux in said core so as to assist the polarizing winding to attract the armature thereo 7. An electromagnetic device, an armature and a magnetic core, a polarizing winding and an operating winding on said core, a condenser in said operating winding and a source of current connected to said polarizing winding, means responsive to the connection of said source 01' current to the polarizing winding for energizing the same and for charging said condenser, means responsive to the charging oi the condenser for energizing said operating winding, and means responsive to the energization oi the operating winding for operating said armature against the core.

8. An electromagnetic device, a magnetic core, an armature pivoted on one end 01' the core,

-a polarizing and an operating winding on said core, a third winding on said core between said operating and polarizing winding, a condenser connected in circuit with said operating winding, said third winding having a source oi'current for maintaining said condenser in a charged condition, means for energizing said polarizing winding to discharge said condenser through said operating winding to energize the same, means responsive to the energimtion oi the operating winding for operating said armature, and means responsive to the opening of the energizing circuit of the polarizing winding for again energizing said condenser from said third winding and for energizing the operating winding in a reverse direction" to restore the armature.

9. In an electromagnetic device, a core, an armature pivoted on one end of the core, a. polarizing and an operating winding inductively connected together on said core, means for energizing said polarizing winding to induce a flow of current in said operating winding to operate 4 said armature, means responsive to the disconnection oi the energizing current from said polarizing winding for inducing a ilow of current to said operating winding in a reversed directi' to restore the armature, and means responsive the energization and deenergization of said polarizing and operating winding for creating a magnetic flux through said core to operate and restore the armature.

10. An electromagnetic device comprising a core, an armature, a polarizing winding on said core, a copper slug on said core having a slot cut reentrant to and parallel to the core, and a 7! magnetic member projecting from the core at right angles to said copper slug to "split the slug intwo' parts forming single turn windings which are connected together in opposition, and

' means responsive to the energization of said polarizing winding for inducing a current flow in said copper slug windings in a direction to operate and restore the armature.

' 11. In an electromagnetic, lay, a magnetic core, an armature, a polarizing and an operating winding on said core, means responsive to the energization of said polarizing winding for energizing said operating winding to create a magnetic flux in said core in a direction to move the armatureagainst the core, said means responsive to the deenergization of said polarizing windwinding, means responsive thereto tor again;

momentarily energizing said operating winding to create a reversed flow oi magnetic flux through said core to move the armature away from the. core, and a magnetic shunt on said core for controlling the flow of magnetic flux.

13. In an electromagnetic device, a magnetic core, a movable armature, a polarizing winding and an operating winding on said core, means for energizing said polarizing winding to create a magnetic flux in said core in a direction to maintain said armature in its normal position,

' means for momentarily energizing said operating winding to create a magnetic flus in said core in the same direction as that created by the polarizing winding, means responsive thereto for armature iroin its normal position and attracting it to the core, means responsive to the deenergization of said polarizing winding ioragain momentarily energizing said core in a reversed direction, and means responsive to said reversed magnetic flux for moving said armature back to its normal position.

14. In an electromagnetic relay, a magnetic core, an armature, a polarizing-and an operating 65 winding on said core, means for energizing both oisaidwindingstocreateamagneticfluxinthe core to attract said armature to the core, means means for energizing 'a reverse direction through and shunt member to attract said armature to I responsive to the deenergization oi! said polarising winding for energizing said operating winding to create a magnetic flux in the reverse diection in said core to move the armature to its normal position, and a magnetic shuntmem- '5 her on said core for controlling a portion of the magnetic flux. 4 15. In an electromagne c relay, a magnetic core, an armature, a pair of windings on said core, means'ior energizing both of said windings 10 to create a magnetic flux in the core to attract the armature, means eiiectiveupon the deenergization of one or said windings for creating a a magnetic flux inthe reverse direction in said ro're to move the armature to its'normal position, 16

and a magnetic shunt member on said core influenced by one of said windings for governing the flow of magnetic flux.

' 16. In an electromagnetic relay, a magnetic.

core, core, means for energizing said windings to create a magnetic flux insuch a direction in said coresoastoattract thearmature,meanacontrolled by one of windings, and a magnetic shunt memberon said ccre governing the flow of magnetic iiux.

1'7. In an electromagnetic relay, a core, an armature, three windings on said core. two of said winding to create a magnetic flux flowing in such a direction in said core to attract the armature, means responsive to the energization of said two windinfli for energizing said third. winding. and means responsive to the energization of said third winding when one of said two windings is thenergized for creating a magnetic flux through said core in a reversed direction to restore the 40 armature to its normal position. a

18. Inlan electromagnetic relay, a magnetic core, a magnetic shunt member extending from said core to a position opposite one end of the core, member and the end of the core, a pair of windings one being on each side of the shunt member rn the core, means for energizing both of said windings for creating -a magnetic flux in a direction through said'core, said armature and said 50 shunt member to attract the armature, and means. eiiective upon the deenergization of one 0! said windings for creating a magnetic flux in said core, armature its normal-position. HAROLD C. FYI.

anarmatureapairotwindingsonsaidli said windings for creating a magnetic flux ina reversed-direction in said'eore Si to repel said'armature backto its normal posiion upon the deenergization oi the other of said I an armature pivoted between said shunt 45 

